The importance of fiber as a dietary component
Diets rich in dietary fiber and prebiotics are those with high levels of
plant foods including fruits, vegetables, whole grains, legumes, nuts
and seeds (Table 2 and Table 3). Such diets are associated with improved
gastrointestinal, cardiovascular and metabolic
health.9 In fact, the American Gut Study showed that
eating 30 plant-based foods per week was associated with the highest
levels of gut microbial diversity.10 In addition to
their high fiber content, these foods also typically have a lower energy
density and lower glycaemic index, and contain important micronutrients,
essential fatty acids and other bioactive substances that contribute to
overall health. EFSA recommends 25g dietary fiber per day for adults to
promote adequate laxation, while recommendations for prevention of type
2 diabetes, cardiovascular disease, colorectal cancer, overweight and
obesity are higher (25-38g/day).11 Some studies have
found a greater risk reduction as more dietary fiber was consumed.
However, this was not consistent across studies. Evidence is currently
too limited to recommend specific types of fiber, so instead a diet rich
in vegetables, fruits, and whole grain cereals is advised. There is less
information available to set dietary fiber recommendations in children
and current guidelines have been based on those for adults and vary
according to energy requirements. EFSA suggests an intake of 2 g/MJ
(megajoules) is considered adequate for normal laxation in children from
the age of one year. There are no guidelines for fibre intake below 1
year of age. As research advances, recommendations should expand to
include individual fibers and consider the effects and physiochemical
properties of specific fiber rich foods in combination with other
supplements.